Topic: Front sprocket is loose - please help.

[bterry]

My front sprocket rotates back and forth, as in the splines on both the shaft and sprocket are worn badly. I've got a new front sprocket coming, but I'm afraid that something is terribly wrong with the shaft. Please tell me it's supposed to be that way.

I've looked through the FAQ's, and searched for an hour - that effort makes me feel like I'm alone on this one.

[Bob Wessner]

Have you inspected the splines? How do they look? Hard to tell from your description, but the front sprocket is not held rigidly in place. There is supposed to be some slight movement or more accurately I guess, play.

[Johnie]

Bob hit it on the head.  You can expect some play on the front sprocket.  You will have the same with a new one, but maybe not as much.  It will tighten up once the chain is on and there is tension there.

[WFO]

No more neutral drops for you mister!

[bterry]

Yeah they do not look like normal splines. I'm no bike guy but they don't look like any other spline I've seen. The sprocket rotates from say 12 o'clock to 1 o'clock - approximately 30 degrees. I'll measure it tonight for a better idea. Maybe a picture.

How hard is it to change the shaft? Are they available (maybe used tranny)?

Do you think the neutral drops are really that bad?

[jaknight]

Hi Terry,

I replaced my front sprocket and shaft several years ago.  Since I was getting a new sprocket, I decided to get a new shaft since I was going in there anyway.  It is not difficult to do......... in fact, it is easy.

The shaft is meant to have some "in & out" play.  In other words, when you are sitting on the bike, the shaft movement would appear from left to right a little bit....... it helps in keeping the front sprocket aligned with the rear sprocket.  There is also some free rotational movement.

Now, my memory is a little fuzzy, but as I recall it there may have been a way that my sprocket lined up best on the shaft at a certain rotational position, besides the 2 bolts holding the sprocket to the plate/shaft assembly.  I may be wrong, I cannot remember for sure.  Before you take your old sprocket off, get a good mental picture (a camera would be better) of things before you actually yank them apart.  If you have manuals, check for the torque values to tighten it all up.

Just remember, its not hard.....

~ ~ ~ jaknight ~ ~ ~

[Bob Wessner]

The sprocket rotates from say 12 o'clock to 1 o'clock - approximately 30 degrees. I'll measure it tonight for a better idea. Maybe a picture.

That 30 degree rotational movement on the shaft is not good. Definitely investigate what is allowing that.

[bterry]

So after looking at it again, the movement wasn't 30 degrees, but it was about a tooth. Still way too much at about 20 degrees. The good news is that most of it was in the old sprocket. Once I put the new one on it hardly moved at all. My manual says that the engine block needs to be separated to remove the shaft, so I'm not going to worry about it for now. There is definitely damage to the shaft, and I will replace it if I ever tear the case apart. For now, I think it will be OK if I keep the neutral drops to a minimum.